Don't look now, but the Flash zombies are after you.
This week, privacy attorney Joseph Malley filed his third lawsuit against major media sites and their ad firms, accusing them of using Flash cookies to illegally collect information about visitors to their websites.
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Malley's defendants aren't exactly Joe Blows -- they're deep-pocketed media companies like ABC, NBC, Disney, and MTV, as well as their respective advertising partners (Quantcast, Clearspring, Specificmedia). All of them use a feature built into Adobe Flash that can set cookies when you load a Flash media file into your browser, which, these days, happens almost any time you view a page with a video ad.
Unlike normal cookies, Flash cookies can "respawn," even after you think you've cleared a website's cookies from your machine. That's why they're called "zombies" -- they come back from the dead to eat brains.
Unlike traditional browser cookies, Flash cookies are relatively unknown to Web users, and they are not controlled through the cookie privacy controls in a browser. That means even if a user thinks they have cleared their computer of tracking objects, they most likely have not....
QuantCast was using the same user ID in its HTML and Flash cookies, and when a user got rid of the former, Quantcast would reach into the Flash storage bin, retrieve the user's old number and reapply it so the customer's browsing history around the net would not be cut off.
After Berkeley researcher Ashkan Soltani published a report detailing the use of Flash cookies on the world's biggest websites, Quantcast says it discontinued the use of them, though that wasn't enough to keep it from getting sued.
Unlike normal browser cookies, which max out at 4K, flash cookies can store up to 100K of information. That's enough for about 30 pages of single-spaced plain text.